Toxicologic evidence of developmental neurotoxicity of environmental chemicals

Developmental neurotoxicity constitutes effects occurring in the offspring primarily as a result of exposure of the mother during pregnancy and lactat ion. To exert their effect, these chemicals or their metabolites must pass the placenta and/or the blood-brain barrier. In experimental animals, expos ure to neurotoxic chemicals during critical periods of brain development ha s induced permanent functional disturbances in the CNS. Although available data suggest that proper animal models exist, only few chemicals have been tested. Neurotoxicity testing is not required by national authorities for c lassification of chemicals. Epidemiological evidence is very limited, but s evere irreversible effects have been observed in humans following in utero exposures to a few known developmental neurotoxicants. The large number of chemicals with a potential for developmental neurotoxicity in humans stress es the importance of generating basic kinetic data on these chemicals based on relevant experimental models. First of all, data are needed on their ab ility to pass the placenta and the developing blood-brain barrier, to accum ulate, and to be metabolized in the placenta and/or the fetus. These kineti c data will be essential in establishing a scientifically based hazard eval uation and risk assessment. (C) 2000 Elsevier Science Ireland Ltd. All righ ts reserved.